The fabrication of semiconductor devices entails numerous processing operations such as parameter measurements and inspections of semiconductor wafers on which the devices are formed during various stages of their development. Current semiconductor wafer inspection and measurement systems are separate stand-alone machines to and from which an attendant often manually transports the semiconductor wafers in a clean room environment. This procedure results in logistical problems and interruptions that slow the manufacturing process.
Semiconductor wafer processing is also undertaken in a minienvironment that is compatible with front-opening interface mechanical standard (FIMS) system equipment. A system designed to incorporate FIMS permits handling of semiconductor wafers inside and outside of clean room facilities by interfacing a clean semiconductor wafer cassette transport box or pod to a clean environmental housing for semiconductor processing equipment or to other clean environments. The system concept entails mating a box door on a front-opening cassette container box to a port door on an equipment enclosure and transferring the cassette into and out of the processing equipment without exposing to outside contamination the semiconductor wafers carried by the cassette.
A standard interface is required for cassette transport boxes intended to control the transport environment of cassettes containing semiconductor wafers. The standard interface addresses the proper transport box orientation for material transfer and maintains continuity between the transport box and semiconductor processing equipment environment to control particulate matter. The FIMS specifications for 300 mm diameter semiconductor wafers are set out in the Semiconductor Equipment and Materials International (SEMI) standard SEMI E47-, E57-, E62-, and E63-0298 (1996–1998).
A FIMS station includes minimum volume, sealed front-opening boxes used for storing and transporting semiconductor wafer cassettes and canopies placed over wafer processing areas of semiconductor processing equipment so that the environments inside the boxes and canopies in cooperation with clean air sources become miniature clean spaces. The standardized cassette container box for 300 mm wafers is called a front-opening unified pod (FOUP). The boxes are made of plastic materials having registration features located relative to one another within, and of sizes characterized by, relatively wide tolerances that can affect equipment alignment precision.
The SEMI standards refer only to stand-alone FIMS stations that are separate from stand-alone measurement and inspection systems. Currently semiconductor wafers are transported back and forth between FIMS stations and the measurement and inspection systems. Information such as wafer tilt and light values must, therefore, be reset and do not transpose from one system to another. Accordingly, processing corrections cannot be easily translated from the measurement and inspection systems to the FIMS station.
Moreover, the amount of time an operator spends moving a wafer cassette transport box to and from the FIMS station results in down time in the FIMS station and the measurement and inspection system. It would, therefore, be advantageous to have an integrated system in which a FIMS station using a standardized interface is compatible with wafer measurement and inspection systems to make better, more flexible use of FIMS stations. It would also be advantageous to provide in such an integrated system a remotely located data processing system that may be shared and scaled.